It is widely known that dyes (e.g., azo dyes, azomethine dyes and anthraquinone dyes), colorants or polymers (for example, rubbers and plastics) are deteriorated by oxidative reactions in which oxygen in air participates. Accordingly, there have been developed various deterioration inhibitors typified by various antioxidant compounds such as phenols and hydroquinones as disclosed, e.g., in JP-A-59-87456, JP-A-59-180557 and JP-A-59-189342 (the term "JP-A" as used herein means an "unexamined published Japanese patent application").
However, none of these conventional deterioration inhibitors is satisfactory in the performance of preventing colorants, dyes, synthetic polymers, etc. from deterioration. Thus, it has been required to develop novel antioxidants.